gistfile1.js

.directive('formMultiple', function() {
  return {
    scope: {
      formMultiple: '=',
    },
    link: function(scope, elm, attr) {
      $(elm).on('keydown', 'input', function() {
        if( $(elm).find('input:last').val() != '') {
          scope.formMultiple.push(scope.formMultipleDefault)
          scope.$digest()
        }
      });
    }
  };
})